Download 213 - jpsaos

Electromagnets with Unequal Currents—Magnetic Field Between 189
Eight pairs of electromagnets are shown below. The current in the left electromagnet is one amp and the
current in the right one is two amps in each case. They are also separated by the same distance, and they
have the same length and diameter. Carefully observe the orientation of the coil and direction of current
flow.
Rank the magnetic fields at the midpoints between the electromagnets from the largest to the smallest.
(The direction to the right is positive, and –5 < -3.)
I = 1 amp
I = 2 amps
I = 1 amp
I = 2 amps
A
B
C
D
E
F
G
H
Largest 1_____ 2_____ 3_____ 4_____ 5_____ 6_____ 7_____ 8_____
Smallest
Or, the magnitude of the magnetic field is the same but not zero for all eight pairs.
Or, the magnitude of the magnetic field is zero for all eight pairs.
Please carefully explain your reasoning.
How sure were you of your ranking? (circle one)
Basically Guessed
Sure
1
2
3
4
5
6
189
7
8
Very Sure
9
10
B. Emerson, C. Hieggelke
Ranking Task Exercises in Physics
213
Electricity and Magnetism